In a new review, the International Chamber of Shipping has concluded that onboard carbon capture and storage is technically feasible and could provide one of the few near-term pathways for reducing tank-to-wake emissions from vessels expected to continue operating on conventional and transition fuels through the 2030s.
Commissioned by ICS and prepared by Lloyd’s Register Advisory, the review assesses the readiness of onboard carbon capture technologies, their operational requirements and the regulatory frameworks that will determine their commercial deployment.
It concludes that OCCS has already been demonstrated at sea across multiple ship types and technology pathways. However, it identifies three main barriers to wider adoption: vessel integration challenges, the availability of carbon reception and disposal infrastructure, and uncertainty over how captured emissions will be recognised under regulatory frameworks.
Amine-based carbon capture systems are identified as the most commercially advanced of the technologies assessed. These reported capture rates of 70-95% and technology readiness levels of approximately 7-8 in marine applications. Other approaches, which include calcium looping, membrane systems, cryogenic capture and thermocatalytic decomposition, are at earlier stages of development or face additional integration challenges.
The review notes that energy consumption, onboard space requirements and CO2 storage capacity remain significant constraints. For many vessel types, escpecially on long-haul routes, the space required for LCO2 storage may become a bigger limitation than OCCS technology.
Chris Waddington, Technical Director at ICS, said: ‘It will be some years before the availability of the green fuels matches demand, and in the meantime OCCS has the potential to make a significant contribution to shipping’s decarbonisation.
‘The numerous technological options and the complex regulatory landscape can be bewildering. Nevertheless, the report addresses many of the questions that shipowners have been asking and provides an excellent starting point for those that are considering OCCS as part of their decarbonisation strategy.’
The study suggests that early deployment is most likely in vessel segments with favourable space and energy characteristics, such as LNG carriers and large tankers. Containerships may be able to accommodate modular systems at the expense of cargo capacity. Retrofitting bulk carriers is expected to be more challenging because of tighter spatial constraints and more limited opportunities for heat recovery.
The report also highlights the importance of downstream carbon management infrastructure. While ship-to-ship transfer, terminal transfer and industrial utilisation projects have been demonstrated, port reception facilities remain limited and captured CO2 must meet strict purity specifications before it can be transported or permanently stored.
The review points out that IMO frameworks, including EEXI, EEDI and CII, do not yet provide defined OCCS crediting mechanisms. By contrast, the EU ETS recognises permanently stored CO2 and makes it the most immediate source of compliance value for shipowners considering investment in onboard capture systems. FuelEU Maritime is still awaiting methodological updates before OCCS can be credited.
Olympia Tsitonaki, Decarbonisation Specialist at Lloyd’s Register Advisory and project lead for the study, said: ‘Shipowners need practical options they can act on now to improve emissions performance while continuing to operate efficiently. This report provides a clearer view of where onboard carbon capture stands today, the challenges still to be addressed, and how it could support compliance and efficiency goals in the years ahead.’
